Extruded racket having two seamless hollow tubes formed with an interconnecting web

ABSTRACT

A racket is made of an aluminum extrusion having two seamless hollow tubes formed with a web of thickness that is more than twice the wall thickness of each tube and is drilled at intervals for receiving the racket strings. The cross-sectional dimension of the extruded racket in a direction perpendicular to the stringing plane is greater than the dimension parallel to the stringing plane. The outside portion of the extrusion is formed with upper and lower grooves for receiving a strip of flexible material that functions for improved balance and weight control and protecting the strings from abrasion, dirt and moisture. The flexible strip may function to help balance and control the weight of the racket through its own weight, supplemented, if necessary, by weights that it may carry.

United States Patent [72] Inventors Peter A. Latham;

Paul E. Brefka, both of LDA Inc., 39 Commercial Wharf, Boston, Mass. 02110 [21] Appl. No. 700,776 [22] Filed Jan. 26, 1968 [45] Patented Dec. 7, 1971 [54] EXTRUDED RACKET HAVING TWO SEAMLESS HOLLOW TUBES FORMED WITH AN INTERCONNECTING WEB 13 Claims, 3 Drawing Figs.

[52] U.S. Cl 273/73 C, 273/73 H [51 Int. Cl A63b 49/02, A63b 49/04, A63b 49/12 [50] Field otSearch 273/73, 73.1, 73.3, 73.4, 73.6, 73.8

[56] References Cited UNITED STATES PATENTS 2,593,714 4/1952 Robinson 273/D1G. 7 3,540,728 11/1970 Palmer 273/73 1 1,452,803 4/1923 Harris 273/73 1,937,787 12/1933 Robinson 273/73 2,552,020 5/1951 Tribelhorn 273/73 3,083,968 4/1963 Takahashi 273/73 3,086,777 4/1963 Lacoste 273/73 3,330,560 7/1967 Higdon 273/73 FOREIGN PATENTS 1,504,630 10/1967 France 273/73 210,485 2/1924 Great Britain.. 273/73 522,222 6/1940 Great Britain 273/73 Primary Examiner- Richard C. Pinkham Assistant Examiner-Richard .l. Apley Attorney-Charles Hieken ABSTRACT: A racket is made of an aluminum extrusion having two seamless hollow tubes formed with a web of thickness that is more than twice the wall thickness of each tube and is drilled at intervals for receiving the racket strings. The crosssectional dimension of the extruded racket in a direction perpendicular to the stringing plane is greater than the dimension parallel to the stringing plane. The outside portion of the extrusion is formed with upper and lower grooves for receiving a strip of flexible material that functions for improved balance and weight control and protecting the strings from abrasion, dirt and moisture. The flexible strip may function to help balance and control the weight of the racket through its own weight, supplemented, if necessary, by weights that it may carry.

EXTRUDED RACKET HAVING TWO SEAMLESS HOLLOW TUBES FORMED WITH AN INTERCONNECTING WEB BACKGROUND OF THE INVENTION The present invention relates in general to rackets and more particularly concerns a novel extruded racket that is relatively easy and inexpensive to construct, facilitates maintaining exceptionally high tension on the racket strings to a desired level without damaging the strings, facilitates achieving proper balance and helps protect the strings from damage caused by abrasion, moisture or dirt where the string is connected to the racket frame.

It is an important object of this invention to provide an improved racket.

It is another object of the invention to provide a sturdy racket that may be economically and relatively easily constructed from extruded material.

It is a further object of the invention to achieve one or more of the preceding objects while maintaining strings in high ten- SIOI'I.

It is a further object of the invention to provide a better playing racket.

It is a further object of the invention to achieve one or more of the preceding objects while establishing a desired control over the racket balance and weight.

It is a further object of the invention to achieve one or more of the preceding objects while providing a protective covering for the strings near the outside perimeter of the racket head to minimize damage from abrasion, moisture or dirt while helping to balance the racket and providing a distinctive and attractive appearance.

It is still further object of the invention to achieve the preceding object while providing a means for supporting supplementary balancing weights, allowing easy adjustment of weight and balance by the player.

SUMMARY OF Tl-lE INVENTION According to the invention, a racket includes a frame-supporting handle means and defining head means supporting racket strings. The frame is formed with means for receiving a flexible strip for both balancing the racket and controlling the weight in a predetermined manner and protecting the strings from damage by abrasion, moisture or dirt.

A feature of the invention is the forming of extrusion into racket shape, the extrusion having two hollow portions that are seamless tubes formed with a solid interconnecting web fonned with rounded openings along at least a predetermined portion of its length corresponding to the head means at intervals for receiving racket strings. Preferably the separation between the seamless tubes is greater than the wall thickness of each tube. Preferably the means in the web defining the opening is rounded to smoothly accommodate the racket string threaded among the holes without imposing any sharp edges on the string that might weaken the string when under tension. The result is a racket that is less flexible for better playing control and facilitates establishing an exceptionally high level of tension in the strings without damaging the strings.

Preferably the extrusion is also formed with grooves along its outer perimeter separated by the interconnecting web for receiving a flexible strip that functions for balance and weight control and to protect the strings from abrasion, moisture or dirt and help achieve a desired degree of balance for the racket. The flexible strip may also accommodate additional supplemental weights.

Numerous other features, objects and advantages of the invention will become apparent from the following specification when read in connection with the accompanying drawing in which:

FIG. I is a plan view of a racket according to the invention;

and

FIG. 3 is a sectional view through section 33 of FIG. 1 to illustrate the preferred form of the extrusion cross section comprising the racket frame.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS With reference now to the drawing and more particularly FIG. 1 thereof, there is shown a plan view of a metal tennis racket according to the invention. The racket comprises an aluminum extrusion 11 formed in the shape of a racket that supports a handle I2, a yoke 13 and strings l4. Yoke I3 is typically riveted to frame 11 to help establish the desired shape and dimensions of the head 15 carrying the strings l4. Yoke 13 may be an aluminum casting appropriately drilled in its sides for accommodating the securing rivets and along its top for receiving the lower ends of the vertical ones of strings 14.

Referring to FIG. 2, there is shown a side view of a metal racket according to the invention in which the flexible strip I6 is visible. The flexible strip 16 functions to protect the strings from abrasion, dirt or moisture, to help achieve a desired degree of balance of the racket and to provide a distinctive attractive appearance to the racket.

Referring to FIG. 3, there is shown an enlarged sectional view through section 3-3 of FIG. 1 illustrating the cross section of the extrusion through an opening accommodating a racket string together with the relationship of the flexible strip and supplemental weights. The extrusion I1 is a unitary structure having a hollow upper portion or seamless tube 21, a hollow lower portion or seamless tube 22 and a solid interconnecting web 23 that may be described as a unitary structure having two seamless hollow tubes 21 and 22 formed with a solid interconnecting web 23 of solid material thickness that is more than twice the wall thickness of each tube. The string opening 24 is preferably rounded as shown so that the strings are never exposed to a sharp edge that might stress the string.

The cross sectional dimension of the extrusion perpendicular to the stringing plane defined by strings I4 is greater than the dimension of the extrusion parallel to the stringing plane. The exterior cross-sectional dimension of each of the two seamless hollow tubes is significantly greater in the direction perpendicular to the stringing plane measured from the center of the extrusion to each end than in the direction parallel to the stringing plane measured across the interconnecting web from one side of the extrusion to the other with each of the tubes having an internal hollow with a shape substantially corresponding to the exterior shape of the tube with the wall thickness of each tube thus being formed therebetween being substantially constant. The dimensions of each internal hollow perpendicular and parallel to the-stringing plane are greater than the tube wall thickness. Each of the hollows is generally rectangular with length and width respectively perpendicular and parallel to the stringing plane and one corner away from the stringing plane having a radius of curvature much greater than that at the other corners.

The extrusion is formed into the racket shape having the curved head frame 15, the handle extension and the throat in between as best seen in FIG. I.

The separation between hollows is greater than the wall thickness of the first tube added to the wall thickness of the second tube, and the interconnecting web is formed with rounded openings 24 along at least the curved head frame for receiving the game racket strings 14 with the separation between adjacent ones of the openings such as 24 corresponding to the separation between adjacent strings 14 when the frame is strung.

Upper hollow portion 2I is also formed with an outwardly and downwardly extending lip 25 to define an upper groove 26. Lower hollow portion 22 is formed with an upwardly and outwardly extending lip 27 to define a lower groove 28.

The lips extend outwardly from the racket shape from portions of each of the tubes nearer to the ends of the extrusion away from the stringing plane than to the stringing plane.

Upper groove 26 and lower groove 28 function to accommodate flexible strip 16 having an upwardly and inwardly extending lip 32 for engagement inside of lip 25 and a downwardly and inwardly extending lip 33 for engagement with lip 27. In addition flexible strip 16 may be formed with a downwardly extending inside lip 34 and an upwardly extending inside lip 35 that define an upper groove 36 and lower groove 37, respectively. The grooves 36 and 37 function to accommodate disclike weights, such as 38, between the strings for providing a desired degree of racket balance. A string 14 is shown in position of diameter corresponding substantially to the narrowest diameter of opening 24. Opening 24 may, if desired, be made large enough to accommodate two strings if it is desired that a particular opening accommodate both a vertically extending and a horizontally extending string. It is, however, preferred that each opening accommodate only a single string, and that, if necessary, separate openings be drilled for vertical strings and separate ones for horizontal strings. For reasons of economy one hole size is preferred of diameter large enough to accept three strings. As is apparent from FIG. 1, the openings are along the head portion of the frame with the separation between adjacent openings corresponding to the separation between adjacent strings.

The particular structure of the flexible strip 31 has a number of advantages. The lips 32-35 coact to firmly keep the flexible strip 31 in a desired position. At the same time lips 33 and 34 perform the additional function of helping to define grooves 36 and 37 for accommodating supplemental weights, if desired. If the density and/or cross-sectional area of flexible strip 31 is appropriately chosen to achieve a predetermined weight per unit length, a desired degree of balance may be obtained without using supplemental weights 38. However, an individual player may desire a different degree of balance and weight which may easily be achieved by inserting an appropriate number of supplemental weights in appropriate positions. The racket is ordinarily preferably balanced so that it is balanced about a line generally perpendicular to the racket length and passing along the bottom web of the yoke 13.

In a specific embodiment of the invention, the diameter of the neck of opening 24 was 0.1 inch and the radius of curvature, 0.062 inches. The height of extrusion 11 was 0.68 inches and its width 0.312 inches. The separation between lips 25 and 27 was 0.368 inches. The span of lips 25 and 27 from the nearest vertical wall was 0.092 inch. The width of each opening in hollow sections 21 and 22 was 0.120 inches, the typical wall thickness being 0.05 inches and slightly narrower where curved adjacent to opening 24. Extrusion 38 was made of black rubber. Weight 38 was a copper or lead weight.

In a preferred form of making the invention, the extrusion is first formed in a flat length, cut to length and then openings like opening 24 drilled with a radius drill. Then the length of extrusion is formed into the racket frame shape and yoke 13 riveted in place. Handle 12 may then be attached, and the racket strung. Then plastic strip 31 may be inserted in place with supplementary weights, if any, appropriately positioned.

The invention has a number of advantages. It is strong, light, economical to fabricate, withstands rugged use, maintains a desired high degree of tension in the strings and is well balanced. It is evident that those skilled in the art may now make numerous modifications of and departures from the specific embodiments described herein without departing from the inventive concepts. Consequently, the invention is to be construed as embracing each and every novel feature present in or possessed by the apparatus and techniques herein disclosed and limited solely by the spirit and scope of the appended claims.

The embodiments of the invention in which an exclusive property or privilege is claimed, are defined as follows:

1. A game racket frame for stringing comprising, an aluminum extrusion that is a unitary structure having two seamless hollow tubes formed with an interconnecting web of material thickness that is more than twice the wall thickness of each tube,

the cross-sectional dimension of said extrusion perpendicular to the stringing plane being greater than the dimension of the extrusion parallel to the stringing plane,

the exterior cross-sectional dimension of each of said tubes being significantly greater in the direction perpendicular to the stringing plane measured from the center of said extrusion to each end in the direction parallel to the stringing plane measured across said interconnecting web from one side of the extrusion to the other,

each of said tubes having an internal hollow with a shape substantially corresponding to the exterior shape of the tube with the said wall thickness thus being formed therebetween being substantially constant,

the dimensions of said internal hollows perpendicular and parallel to said stringing plane being greater than said tube wall thickness,

said extrusion being formed into a racket shape having a curved head frame, throat and handle extension.

2. A game racket frame for stringing in accordance with claim 1 wherein the separation between the internal hollows of said tubes is greater than the wall thickness of the first of said tubes added to the wall thickness of the second of said tubes,

and said interconnecting web is formed with rounded openings along at least a predetermined intermediate portion of its length corresponding to said curved head frame for receiving game racket strings with the separation between adjacent ones of said openings corresponding to the separation between adjacent strings when said frame is strung.

3. A game racket for stringing in accordance with claim 22 wherein said shape of said hollows is generally rectangular with length and width respectively perpendicular and parallel to said stringing plane and one corner away from the stringing plane having a radius of curvature much greater than that at the other comers thereof.

4. A game racket extrusion for stringing in accordance with claim I wherein said extrusion is formed with lips extending outwardly of the racket shape from portions of each of said tubes nearer to the ends of said extrusion away from said stringing plane than to said stringing plane.

5. A game racket frame in accordance with claim 1 where the thickness of said web corresponds substantially to the width of said tubes.

6. A game racket frame in accordance with claim I wherein said extrusion is formed with means for receiving a flexible strip,

said frame being formed for supporting handle means and defining head means for supporting strings,

a flexible strip carried by said means for receiving about the perimeter of said head means and coacting with same frame to comprise means for balancing and controlling the weight of said racket and for protecting the racket strings from damage by abrasion, moisture or dirt.

7. A game racket frame in accordance with claim 6 wherein said extrusion is also formed with grooves along its outer perimeter separated by said interconnecting web comprising said means for receiving,

said flexible strip residing in said grooves.

8. A game racket frame in accordance with claim 6 wherein said flexible strip is formed with means for removably supporting elemental weights.

9. A game racket frame in accordance with claim 8 and further comprising at least one of said elemental weights carried by said means for removably supporting.

10. A method of making the game racket frame of claim 1 which method includes the steps of,

forming said extrusion,

drilling said rounded openings in said web along said predetermined intermediate portion of its length,

claim 11 and further including the step of forming said extrusion with grooves along its outer perimeter separated by said interconnecting web,

and inserting a flexible strip in the latter grooves. 13. A method of making a game racket in accordance with claim 11 and further including the steps of,

forming said extrusion with grooves along its outer perimeter separated by said interconnecting web, inserting supplemental weights in a flexible strip, and inserting said flexible strip carrying said supplemental weights in the latter grooves.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, 5,5 Dated D em er 7, 1971 Inventor(s) Peter A. Latham & Paul E. Brefka It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column I, line 9, after "end", insert than Column 4, line 3U, change "22" to l Signed and sealed this 6th day of March 1973.

(SEAL) Attest:

EDWARD M.FLETCHER JR. Attesting Officer ROBERT GOTTSCHALK Commissioner of Patents 

1. A game racket frame for stringing comprising, an aluminum extrusion that is a unitary structure having two seamless hollow tubes formed with an interconnecting web of material thickness that is more than twice the wall thickness of each tube, the cross-sectional dimension of said extrusion perpendicular to the stringing plane being greater than the dimension of the extrusion parallel to the stringing plane, the exterior cross-sectional dimension of each of said tubes being significantly greater in the direction perpendicular to the stringing plane measured from the center of said extrusion to each end in the direction parallel to the stringing plane measured across said interconnecting web from one side of the extrusion to the other, each of said tubes having an internal hollow with a shape substantially corresponding to the exterior shape of the tube with the said wall thickness thus being formed therebetween being substantially constant, the dimensions of said internal hollows perpendicular and parallel to said stringing plane being greater than said tube wall thickness, said extrusion being formed into a racket shape having a curved head frame, throat and handle extension.
 2. A game racket frame for stringing in accordance with claim 1 wherein the separation between the internal hollows of said tubes is greater than the wall thickness of the first of said tubes added to the wall thickness of the second of said tubes, and said interconnecting web is formed with rounded openings along at least a predetermined intermediate portion of its length corresponding to said curved head frame for receiving game racket strings with the separation between adjacent ones of said openings corresponding to the separation between adjacent strings when said frame is strung.
 3. A game racket for stringing in accordance with claim 1 wherein said shape of said hollows is generally rectangular with length and width respectively perpendicular and parallel to said stringing plane and one corner away from the stringing plane having a radius of curvature much greater than that at the other corners thereof.
 4. A game racket extrusion for stringing in accordance with claim 1 wherein said extrusion is formed with lips extending outwardly of the racket shape from portions of each of said tubes nearer to the ends of said extrusion away from said stringing plane than to said stringing plane.
 5. A game racket frame in accordance with claim 1 where the thickness of said web corresponds substantially to the width of said tubes.
 6. A game racket frame in accordance with claim 1 wherein said extrusion is formed with means for receiving a flexible strip, saiD frame being formed for supporting handle means and defining head means for supporting strings, a flexible strip carried by said means for receiving about the perimeter of said head means and coacting with same frame to comprise means for balancing and controlling the weight of said racket and for protecting the racket strings from damage by abrasion, moisture or dirt.
 7. A game racket frame in accordance with claim 6 wherein said extrusion is also formed with grooves along its outer perimeter separated by said interconnecting web comprising said means for receiving, said flexible strip residing in said grooves.
 8. A game racket frame in accordance with claim 6 wherein said flexible strip is formed with means for removably supporting elemental weights.
 9. A game racket frame in accordance with claim 8 and further comprising at least one of said elemental weights carried by said means for removably supporting.
 10. A method of making the game racket frame of claim 1 which method includes the steps of, forming said extrusion, drilling said rounded openings in said web along said predetermined intermediate portion of its length, and forming said extrusion into the shape of a racket having a head portion embracing said predetermined intermediate portion of the web length and a handle portion for supporting handle means.
 11. A method of making a game racket frame in accordance with claim 10 and further including the step of, fastening opposed portions of said extrusion to a yoke along substantially the boundary between said handle portion and said head portion.
 12. A method of making a game racket is accordance with claim 11 and further including the step of forming said extrusion with grooves along its outer perimeter separated by said interconnecting web, and inserting a flexible strip in the latter grooves.
 13. A method of making a game racket in accordance with claim 11 and further including the steps of, forming said extrusion with grooves along its outer perimeter separated by said interconnecting web, inserting supplemental weights in a flexible strip, and inserting said flexible strip carrying said supplemental weights in the latter grooves. 